Screening And Identification Of Wheat Mutants Mutagenesed By EMS

Germplasm resources with high yield,high quality and strong resistance are the key to wheat breeding.EMS artificial mutagenesis is one of the important strategies of wheat new germplasm development and functional genomics research.In this study,the M2 and above generation mutant populations obtained from the previous research with 0.7%EMS treated the Sumai No.3 and the 6VS/6AL translocation lines(Nanong 9918,92R137),which were tested for two consecutive years in this study.After the investigation of the major agronomic traits such as plant height,panicle and leaf and yield in the field,and identification of disease resistance using detached-leaf assay and natural assay,a group of genetically stable wheat mutants were selected.The main results of this study are as follows:1 Identification and analysis of the Sumai No.3 EMS induced mutants59 stable dwarf mutants were screened from 156 mutants of Sumai No.3 background,All dwarf mutants have a culm-reduce degree of 20%-40%,a few with culm-reduce of 40%-50%,or even 50%-70%,and there are some differences in the plant height of the mutants grown in the field and greenhouse respectively.From this,the tiller,grain shape and Spike-shaped mutants were also screened.Sunai No.3 carries the high resistant gene Fhbl to wheat Fusarium head blight,but Sumai No.3 is high susceptible to wheat powdery mildew..This study identified the natural pathogens in the field and artificial inoculation of pathogens,twenty of FHB susceptible mutants,one of powdery mildew moderately susceptible mutant and five of leaf-witheredmutants from 156 Sumai No.3 background mutants.were screened.2 Identification and analysis of the 92R137 EMS induced mutants51 stable dwarf mutants were screened from 152 92R137 background mutants,The culm-reduce of all dwarf mutants is similar to Sumai No.3 background mutants,have a culm-reduce degree of 20%-40%,a few with culm-reduce of 40%-50%,or even 50%-70%,and there are some differences in the plant height of the mutants grown in the field and greenhouse respectively.thirteen of branching spike mutants,two of large spike mutants,1 part of lesions,and 1 stripe mutant were also obtained.3 Identification and analysis of the Nanong 9918 EMS induced mutantsSeven of the self-necrotic green leaf color mutants were screened from 45 mutants in Nannong 9918 background.An auto-necrotic interleaf-green stable mutant of M3 generation Nannong 9918 background(6VS/6AL translocation line with high resistance to powdery mildew)was crossed to a high-yield powdery mildew susceptible variety Nannong 06Y86(mother parent).The F1 plants showing resistance to powdery mildew are the true hybrids,and all of them showed normal leaf color.The ratio of normal green plants and interleaf green plants in the self-crossing F2 generation was close to 1:3,which showed that the interleaf green mutant phenotype was controlled by a single recessive gene according to the chi-square test.4 Identification and analysis of mutant agronomic traitsBecause plant height and other agronomic traits are closely related,the results of identification of dwarf mutant show that with the decrease of plant height,most traits shuch as the number of tillers,effective tillers,panicle length,the number of panicles,grain length,grain width,and 100-grain weight of most mutants were also decreased,and some reached significant differences compared with the wild type.However there were also several dwarf mutants,which showed the number of tillers or the 100-grain weight increased,and could be used as favorable mutants.Furthermore,the seed α-amylase activity induced by gibberellin assay was performed and proved that the dwarf trait of the above mutant material was not related to the gibberellin signaling pathway.The background of the translocation lines(92R137 background)were identified by 6VS specific molecular markers and the results confirmed that the genetic background of all translocation mutants was correct.